Cardarine

weak data

Also seen as: GW501516, GW50156, GW-501516, Endurobol

The Dose Guy’s verdict

Sep 1, 2026
4 sources

Cardarine works. The lipid numbers move, the endurance goes up, and people feel the difference inside a week. But cardarine’s development died for a reason: rodent cancer models grew tumors, and no one has run the compound long enough in humans to know whether that signal carries over. You are making a bet that mouse cancer models do not predict yours. That bet might be right. I would not make it.

Would I take it?Caution, the cancer asterisk is real.

What it is

Cardarine is a PPAR-delta agonist, not a stimulant, not a hormone, and not a peptide. It flips a metabolic switch: cells burn more fat and less glucose for fuel, which is why endurance athletes and the cutting crowd both reach for it. In human muscle cells the shift is measurable: more fat oxidation, less glucose use, a fuel-preference change rather than a raw increase in total burn. Short human trials confirmed the metabolic story with clean lipid-panel shifts and liver-fat reductions.

The catch is the safety shelf. GSK killed the program after the rodent cancer signal. Those were cancer-prone models, transgenic and chemically induced, and the community points to that context constantly. Fairly. But the studies that would settle the question in humans were never run, because the rodent signal was bad enough that nobody wanted to fund them.

What the research shows

The human metabolic data is real but short: weeks, not years. The cancer data is rodent, long, and ugly.

Among 268 people with low HDL cholesterol, 12 weeks of cardarine increased HDL cholesterol by up to 16.9% at 10 mg daily and reduced triglycerides by 16.9%.ATVB 2012 · n=268 · 12wk

In six moderately overweight men, 10 mg daily for 2 weeks reduced liver fat by 20% and fasting plasma triglycerides by 30%.Diabetes 2008 · RCT · n=6 arm · 2wk

In a transgenic mouse model, cardarine shortened mammary carcinoma latency from 12 months to 5 months.Cancer Res 2013 · transgenic mice

In mice with mutant KRAS pancreatic cells, cardarine strongly accelerated progression from pre-cancerous lesions to ductal adenocarcinoma.Nat Commun 2022 · KRAS mice

Realistic protocols

The community runs cardarine at 10 to 20 mg daily, oral, usually in cycles of 8 to 12 weeks. Most people start at 10 mg and stay there. 20 mg is the ceiling that shows up in forum logs, and the human trials topped out at 10 mg. The effect comes on fast, often within the first few days, as a noticeable bump in cardio endurance and a leaner look that compounds over weeks.

Cycle length is the real decision. Every extra week is more time on a compound whose long-term safety in humans is genuinely unknown, and the metabolic benefits plateau rather than climbing linearly. Shorter cycles, six to eight weeks, are the cautious move, with bloodwork before and after.

There is no good argument for running cardarine year-round. If the goal is lipid improvement, a statin does the job with decades of safety data. If the goal is endurance or cutting, cardarine does its job inside a cycle and you keep most of the conditioning after you stop.

Start10 mg/dayOral, once daily. Most people feel the endurance shift within days.

Ceiling20 mg/dayForum ceiling. Human trial data only covers 10 mg.

Cycle6–8 weeksShorter is safer. The benefits plateau, the risk does not.

BloodworkPre and postLiver enzymes, lipid panel. Non-negotiable on this compound.

Side effects

The short human trials did not report a safety signal, and they were too short to see one. The concern is what those trials cannot answer:

anecdotalMost users report no acute side effects at common doses.

monitorLiver enzymes. One published case involved rhabdomyolysis in a person using cardarine with ostarine, and the contribution of each compound is unclear. Check your liver panel.

unknownMulti-organ tumor promotion in long-duration rodent studies. No long-term human safety data exists. The cancer question is open, not answered.